The effects of carbon nanoparticles on thermal and dielectric properties of bisphenol A polycarbonate

Abstract

A series of composite films consisting of bisphenol A polycarbonate (BAPC) and carbon black (CB) as nanofillers were prepared by solution mixing followed by film casting. The influence of both CB content and temperature on thermal and dielectric properties of BAPC was investigated. X-Ray diffraction patterns show semicrystalline nature of the prepared films. The thermal and dielectric properties were carried out as a function of frequency in the range from 20 Hz to 3 MHz, temperature in the range from 20 to 80°C for concentrations 0, 1, 3, 5, 7, 10, and 15 wt% CB. Differential scanning calorimetric results show a decrease in the glass transition temperature and apparent activation energy at decomposition temperature when the CB content increases. The dielectric measurements show that the dielectric constant ( ε′) and alternating current conductivity increase with CB content and also with the temperature. However, the ε′ and dissipation factor decrease with frequency. The increase in ε′ with temperature is due to the formation of new dipoles or accumulation of charge carriers in a nanoparticle–polymer interface. Parameters relating to thermal and dielectric properties of these composites can be controlled by adjusting the CB nanoparticles content in the BAPC matrix and temperature. It could be concluded that the obtained composites should be desirable candidates for high ε′ materials in embedded capacitor applications.